Capacitors are commonly-used electrical components in semiconductor circuitry, for example memory circuitry such as DRAM circuitry. A typical capacitor is comprised of two conductive electrodes separated by a non-conducting capacitor dielectric region. As integrated circuit density increases, there is a continuing challenge to maintain sufficiently high storage capacitance despite decreasing capacitor area. One way of increasing cell capacitance is through cell structure techniques. Such techniques include three-dimensional cell capacitors, such as trenched and stacked capacitors. Other ways of increasing cell capacitance include the development and utilization of new materials for one or both of the electrodes and the capacitor dielectric region.
One type of capacitor utilizes a semiconductor-insulator-semiconductor (SIS) construction. Capacitance increase can result for the same capacitor dielectric region by making one or both of the electrodes metallic, for example forming semiconductor-insulator-metal (SIM), metal-insulator-semiconductor (MIS) or metal-insulator-metal (MIM) capacitors. However, capacitance increase from such constructions can also cause increased undesired leakage current across the capacitor. Further, the deposition of oxide containing capacitor dielectric regions, as well as deposition of certain metal containing capacitor electrode materials, can be problematic in the fabrication of metal containing capacitor electrodes.
While the invention was motivated in addressing the above described issues, it is in no way so limited. The invention is only limited by the accompanying claims as literally worded, without interpretative or other limiting reference to the specification, and in accordance with the doctrine of equivalents.